1. Field of the Invention
The invention relates to a lamp, with a light-emitting unit, at least two separate contact modules and an electrical connection between the light-emitting unit and the contact modules, wherein each contact module has at least one electrical contact for connecting to a corresponding lampholder. The invention further relates to a system comprising a lamp and a lampholder, wherein for operation in the lampholder the lamp is designed corresponding to the lampholder.
2. Description of the Prior Art
Lamps with separate contact modules are used at present, especially as gas-discharge lamps, especially fluorescent lamps. Fluorescent lamps are mostly of tubular shape, so they are also called fluorescent tubes. These lamps differ from classical incandescent bulbs in that two separate contact modules are provided, with which electrical contact can be made between the lamp and the lampholder of a luminaire.
The contact module is understood as the part of a lamp that is provided directly for connection to the lampholder of a luminaire. In particular it is the part of a lamp that is designed corresponding to the lampholder, so that the lamp can be received in the lampholder. In the case of an incandescent bulb, for example the thread as a whole can be understood as the contact module, whereas in the case of conventional fluorescent tubes the end-face sections or end faces can be regarded as contact modules. Moreover, contact modules that are a certain distance apart, i.e. separate, are to be understood in particular as those between which a light-emitting unit of the lamp is provided, which applies in particular in the case of tubular lamps. Alternatively or additionally, two contact modules can be regarded as separate if light is emitted outwards between regions of the contact modules that are adjacent to one another.
“Lampholder” means, in the sense of the invention, a component of the luminaire that serves for receiving and interchangeably fastening the lamp to be operated with the luminaire.
In the case of fluorescent tubes, the two contact modules are often provided on opposite ends of the lamp. As a rule two contacts for electrical connection of the lamp to the lampholder are provided on each contact module. The actual light-emitting unit, which emits light under voltage, is connected via an electrical connection to the two contact modules.
If lamps with two contact modules that are a certain distance apart are inserted in a lampholder of a luminaire, the lamp can already be connected electrically conducting with the lampholder via one of the contact modules, while another contact module is not yet inserted in the lampholder. In this partially assembled state the user may unintentionally come in contact with the contact module that is not yet inserted in the lampholder. This is not a problem with gas-discharge lamps, because owing to their design, the user cannot receive an electric shock by touching the still accessible contact module.
The situation is different with lamps with which there is already increased conductivity between the electrical contacts of the two contact modules in the partially assembled state. This can be the case for example with light-emitting units comprising LEDs (light-emitting diodes). For such lamps it is therefore recommended for the contacts to be as close together as possible, to prevent a user receiving an electric shock if insufficient care is taken when inserting the lamp in a lampholder of a luminaire.
However, this is not possible when gas-discharge lamps, such as ordinary fluorescent tubes, are to be replaced with other lamps. In this case the lamps must be designed to be compatible with the existing lampholders provided for receiving fluorescent tubes.
The connections of conventional lampholders F for use with fluorescent tubes LS are, shown schematically in FIG. 1. As shown here, the fluorescent tubes LS are inserted upwards into the lampholder F. The lampholder F has a lampholder socket FS on both sides, on which two contacts K are provided, each connected to two contacts of the lamp. In FIG. 1A, the left lampholder socket FS has a lower contact L, on which the operating voltage is applied. The two upper contacts K of the two lampholder sockets FS are connected together via a so-called starter S. The lower contact represents the non-live neutral conductor N. However, there are also lampholders for operating fluorescent tubes as shown in FIG. 1B. In these, the lower contacts of the two lampholder sockets are connected together via a starter S, whereas the two upper contacts have the live contact L and the zero-voltage contact N. However, it can also be envisaged that the live and zero-voltage contacts L,N are provided sometimes below and sometimes above on the opposite lampholder sockets FS. Corresponding lampholders are shown in FIGS. 1C and 1D.
In order to avoid problems that arise when the lampholders for the use of fluorescent tubes are for example operated with LED-based lamps, until now a rewiring of existing lampholders, or luminaires has been proposed. This rewiring can take the form of supplying current to the lamp via two contacts of one and the same contact module. Corresponding lamps are also known as “conversion LED units”. Another contact module is then provided just for inserting and holding the lamp in the lampholder, without an electrical connection having to be made there between the lampholder and the lamp.
Drawbacks of such solutions are the high cost of rewiring the lampholders and the fact that correspondingly rewired lampholders can no longer be operated with conventional fluorescent tubes.
Therefore the technical problem to be solved by the present invention is to design and elaborate lamps and systems in each case of the kind stated above in such a way that these can be operated reliably without using conventional gas-discharge lamps.